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Valentin Aranha dos Santos, Leopold Schmetterer, Gerold Aschinger, Gerhard Garhofer, Rene Marcel Werkmeister; Visualization of tear film dynamics using optical coherence tomography.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5718.
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© ARVO (1962-2015); The Authors (2016-present)
To visualize tear film dynamics without dye instillation using ultrahigh-resolution optical coherence tomography (OCT).
Five healthy volunteers and five subjects with dry eye syndrome were included in the study. 40 OCT data sets of the central cornea composed of 10 volumes with 256x256 A-scans were acquired with an ultrahigh-resolution OCT system based on a 800 nm Ti:Sapphire laser with 170 nm bandwidth. Measurement started immediately after blinking and lasted 14 seconds. The post processing with custom Matlab software is relying on an efficient delay estimator that allows to measure the tear film thickness in each A-scan. The thickness estimation was validated in vitro using fabricated silicon samples and comparing estimated thickness with a reference method (F20-UVX-thinfilm analyzer, Filmetrics Inc., San Diego, CA, USA). Repeatability was investigated using replicate measurement done in one specific subject immediately after the first measurement under identical conditions.
En face tear film thickness 2D maps obtained from each volume dataset were generated allowing to visualize the dynamics of the tear film thinning. The area of imaging on the ocular surface is shown in Fig. 1(a) and Fig. 1(b) depicts one corresponding tear film thickness map. Fig. 2(a) shows a tear film dynamics measurement in a healthy subject. One can observe a thinning of around 2.5 microns after 9 s. Fig. 2(b) shows replicate measurements under identical conditions as Fig. 2(a). When comparing Figs. 2(a) and 2(b), similar tear film dynamics can be observed, indicating that the measured tear film dynamics after blinking are repeatable in the same subject.
An OCT-based approach for noninvasive visualization of tear film dynamics was reported. Repeatable tear film dynamics were observed. The approach is suitable for use in clinical settings and could be used for studying dry eye syndrome and to quantify the dynamic efficacy of dry eye treatments.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Fig. 1 (a) Slit lamp image of the front surface depicting the imaged area. (b) En face tear film thickness (TFT) map measured in a healthy subject.
Fig. 2 Visualization of tear film dynamics in a healthy subject. (a) En face tear film thickness (TFT) maps measured directly after blink. (b) Repetition of the measurement in identical conditions as in Fig. 2(a). Similar thinning pattern is observed in each series.
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